System and method for gapping an embedded magnetic device

ABSTRACT

Disclosed is an apparatus and method for a magnetic component. The method of an example embodiment includes: forming a feature on a substrate, the feature being a depression defining an inside surface; disposing a first conductive pattern on the substrate and the inside surface of the feature; disposing a permeability material on the inside surface of the feature and the first conductive pattern; disposing a substrate material on the substrate and the feature; disposing a second conductive pattern on the substrate material, the second conductive pattern substantially matching the first conductive pattern to wrap the permeability material between the first conductive pattern and the second conductive pattern producing a winding type structure electrically coupling the first conductive pattern and the second conductive pattern in electrical connection to define at least one electrical circuit to facilitate a magnetic field in the permeability material; and gapping the permeability material to remove at least a portion of the permeability material to produce a gap in the at least a portion of the permeability material.

PRIORITY APPLICATIONS

This is a divisional patent application claiming priority to U.S. patentapplication Ser. No. 15/168,185, filed on May 30, 2016; which is acontinuation-in-part patent application claiming priority to U.S. patentapplication Ser. No. 12/329,887, filed on Dec. 8, 2008, which is adivisional application claiming priority to U.S. non-provisional patentapplication Ser. No. 11/233,824, filed on Sep. 22, 2005, which are intheir entirety incorporated herein by reference.

BACKGROUND

The disclosure generally relates to magnetic components.

A wide range of electronic devices may have various magnetic components.Magnetic components may be capable of providing various functions. Forexample, magnetic components in electronic devices may function astransformers, inductors, filters, and so forth. Commonly, in order tohave magnetic properties, magnetic components may comprise of anassembly of one or more wires wound around a material havingpermeability properties such as ferromagnetic material having a toroidaltype shape, a rod type shape, etc. When a current is applied to the oneor more wires, the component may produce a magnetic field, which may beutilized to address a wide range of electrical needs associated withelectronic devices.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings, in which likereferences may indicate similar elements and in which:

FIG. 1 illustrates a perspective exploded view of a magnetic componentin accordance with one embodiment;

FIGS. 2A-2B illustrate a top view and a sectional view of a substratehaving a feature in accordance with one embodiment;

FIGS. 3A-3C illustrate a top view, a section view, and a detail view ofa substrate having a feature and a conductive pattern disposed withinthe feature in accordance with one embodiment;

FIG. 4 illustrates a perspective exploded view of a magnetic componentin accordance with another embodiment;

FIG. 5 illustrates a schematic of a magnetic component in accordancewith an embodiment;

FIG. 6 illustrates a schematic of a magnetic component in accordancewith another embodiment;

FIG. 7 illustrates a schematic of a magnetic component in accordancewith another embodiment;

FIG. 8 illustrates a schematic of a magnetic component in accordancewith another embodiment;

FIG. 9 illustrates a flow chart of one embodiment of a process forproducing a magnetic component;

FIGS. 10a and 10b depict inductors wound on solenoid (FIG. 10a ) andtoroid (FIG. 10b ) shaped cores;

FIGS. 11a and 11b show a top view and isometric view of an embeddedmagnetic inductor in an example embodiment;

FIGS. 12a and 12b show examples of embedded magnetic devices implementedon rectangular and multi-hole (binocular) core structures;

FIG. 13 shows an isometric diagram of an embedded magnetic device in anexample embodiment being trimmed while the inductance is monitored by aninductance meter;

FIG. 14 depicts a four layer embedded magnetic device in an exampleembodiment where the gap is cut after application of the inner layer andcovered by the outer layers;

FIGS. 15a and 15b depict how a power converter module in an exampleembodiment can be implemented with embedded magnetics;

FIGS. 16a, 16b, and 16c depict variations of example embodiments wherethe trim-cut or gap can be applied during the device fabrication; and

FIG. 17 is a flow chart illustrating an example embodiment of a methodas described herein.

DETAILED DESCRIPTION

In the following description, embodiments will be disclosed. Forpurposes of explanation, specific numbers, materials, and/orconfigurations are set forth in order to provide a thoroughunderstanding of the embodiments. However, it will also be apparent tothose skilled in the art that the embodiments may be practiced withoutone or more of the specific details, or with other approaches,materials, components, etc. In other instances, well-known structures,materials, and/or operations are not shown and/or described in detail toavoid obscuring the embodiments. Accordingly, in some instances,features are omitted and/or simplified in order to not obscure thedisclosed embodiments. Furthermore, it is understood that theembodiments shown in the figures are illustrative representations andare not necessarily drawn to scale.

References throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, material, and/orcharacteristic described in connection with the embodiment is includedin at least one embodiment. Thus, the appearances of the phrases “in oneembodiment” and/or “in an embodiment” in various places throughout thisspecification are not necessarily all referring to the same embodiment.Furthermore, the particular features, structures, materials, and/orcharacteristics may be combined in any suitable manner in one or moreembodiments.

For the purposes of the subject matter disclosed herein, substrates mayinclude a wide range of substrates such as, but not limited to, plastictype substrates, semiconductor type substrates, and other insulatingmaterial substrates, including polyimide, fiberglass, and ceramic.Accordingly, it should appreciated by those skilled in the art thattypes of substrates may vary widely based at least in part on itsapplication. However, for the purposes of describing the subject matter,references may be made to a substrate along with some example types, butthe subject matter is not limited to a type of substrate. Additionally,for the purposes of describing various embodiments, references may bemade to magnetic components. However, it should be appreciated by thoseskilled in the relevant art that magnetic components may include a widevariety of magnetic components such as, but not limited to transformertype components, inductor type components, filter type components, andso forth, and accordingly, the claimed subject matter is not limited inscope in these respects.

Turning now to the figures, FIG. 1 illustrates a perspective explodedview of a magnetic component in accordance with one embodiment. As shownin FIG. 1, magnetic component 100 may comprise of a substrate 102 havinga first surface 104 and a feature 106. A first conductive pattern 108may be disposed on the feature 106. A permeability material 110 may bedisposed within the feature 106. Additionally, in the illustratedembodiment, a substrate material 112 may be disposed on the firstsurface 104 and on the feature 106, thereby forming a second surface114. Disposed on the second surface 114 may be a second conductivepattern 116. As will be further described in detail, first conductivepattern 108 and second conductive pattern 116 cooperate to be capable offacilitating magnetic properties of permeability material 110 inaccordance with various embodiments.

It should be appreciated that FIG. 1 illustrates an exploded view todescribe an embodiment of the claimed subject matter, and accordingly,as will be described in further detail, magnetic component 100 may havepermeability material 110 substantially enclosed within feature 106 withsubstrate material 112 substantially covering the permeability material110. First conductive pattern 106 and second conductive pattern 116 maysubstantially surround the permeability material, thereby forming awinding type relationship.

Continuing to refer to FIG. 1, substrate 102 is shown having asubstantially rectangular type shape. However, it should be appreciatedthat substrate 102 may have any type of shape such as, but not limitedto, substantially circular, substantially square, or any other type ofpolygonal shape. Additionally, substrate 102 may comprise of many typesof material such as, but not limited to, material suitable for printedcircuit boards (PCBs), various plastic type materials, material suitablefor injection molding and so forth. For example, in one embodiment,substrate 102 may comprise of a thermoplastic type material such as, butnot limited to, polyetherimide (PEI) type material. In anotherembodiment, substrate 102 may comprise of a resin type material that maybe suitable for injection type molding such as, but not limited to,liquid crystal polymer type material. It should be appreciated by thoseskilled in the relevant art that the shape and materials described aremerely examples, and the claimed subject matter is not limited in scopein these respects.

In FIG. 1, feature 106 is illustrated as a cup type feature below thefirst surface 104. That is, feature 106 may comprise of a depression inthe first surface 104 of substrate 102. Further, in the illustratedembodiment of FIG. 1, feature 106 may comprise of a toroidal type shapedepression below first surface 104 into the body of substrate 102.However, it should be appreciated by those skilled in the relevant artthat feature 106 may have a wide range of shapes such as, but notlimited to, a rod type shape, oblong type shape, and so forth, andaccordingly, the claimed subject matter is not limited in scope in theserespects.

A variety of approaches may be utilized in order to facilitate formationof feature 106. For example, in one embodiment, feature 106 may beformed by utilizing a lithography type process such as, but not limitedto photolithography. In another embodiment, feature 106 may be formed byutilizing a machining type process such as, but not limited to, amicromachining process. Various approaches may be utilized to facilitateformation of a feature, and accordingly, the claimed subject matter isnot limited to a particular approach.

As shown in FIG. 1, first conductive pattern 108 may be disposed in apattern around the inside of feature 106. In the illustrated embodiment,first conductive pattern 108 may be disposed in a manner whereby firstconductive pattern 108 substantially lines portions of the insidesurfaces of the feature 106. Here too, a variety of approaches may beutilized in order to dispose the first conductive pattern 108. In oneembodiment, first conductive pattern 108 may be disposed by utilizing astamping type approach such as, but not limited to, stamping aconductive pattern on a substrate. In another embodiment, firstconductive pattern 108 may be disposed by utilizing a plating typeapproach such as, but not limited to, chemical and/or electroplating aconductive pattern on a substrate. In another embodiment, firstconductive pattern 108 may be disposed by utilizing a lithography typeapproach such as, but not limited to, photolithography. In yet anotherembodiment, a structuring type approach such as, but not limited to,laser structuring type approach may be utilized to dispose firstconductive pattern 108. Various approaches may be utilized to dispose aconductive pattern, and accordingly, the claimed subject matter is notlimited to a particular approach.

First conductive pattern 108 may comprise of a wide variety of materialssuch as, but not limited to, copper, aluminum, gold, and various typesof conductive tracing materials. Accordingly, the claimed subject matteris not limited in scope in these respects. Continuing to refer to FIG.1, permeability material 110 is shown as having a shape based at leastin part on the shape of the feature 106. That is, permeability material110 may have a substantially toroidal shape that may substantially fitwithin the feature 106. In the embodiment of FIG. 1, permeabilitymaterial 110 may be shown as a separate solid object, where the solidobject may be placed within the feature 106 by various methods such as,but not limited to, utilizing a pick and place machine. However, inanother embodiment, permeability material 110 may be of a liquid typeform whereby the liquid type form may be poured into a feature. Inanother embodiment, permeability material 110 may be in the form of apowder type material whereby the powder type material may be disposedinto a feature. In yet another embodiment, permeability material 110 maycomprise of material that may be utilized with a vibration based typeapproach to facilitate placement of the permeability materialsubstantially within the feature 106. That is, a method by which avibration type machine may be utilized. Accordingly, the claimed subjectmatter is not limited in scope in these respects.

Permeability material 110 may comprise of a wide variety of materialssuch as, but not limited to, ferromagnetic type materials that mayinclude ferrite type materials, iron type material, metal typematerials, metal alloy type materials, and so forth. Additionally,permeability material 110 may comprise of materials based at least inpart on the particular utilization of a magnetic component. For example,a magnetic component to be utilized as an isolation transformer mayinclude a permeability material having a relatively high permeability,such as, but not limited to 10000 Henry per meter. In another example, amagnetic component to be utilized as a common mode filter may include apermeability material having a moderate permeability such as, but notlimited to, 1000 Henry per meter. Further, as previously alluded to, thesize and shape of the permeability material 110 may be based at least inpart on the utilization of the magnetic component as well. Accordingly,the claimed subject matter is not limited in scope in these respects.

In FIG. 1, for the purposes of describing the embodiment, substratematerial 112 may be shown as a thin layer. However, the thin layer maybe representative of one or more layers of printed circuit layers to bedisposed on the first surface 104 of the substrate 102 and does notnecessarily denote a single piece of substrate material, but it alsocould be a single piece of substrate material. Additionally, thesubstrate material 112 does not necessarily need to substantially matchthe material of the substrate 102 and may be of a different material.For example, in one embodiment, the substrate material 112 may includevarious lamination layers that facilitate a build-up of circuit layers.In another embodiment, a liquid type material may be disposed on the ona substrate such as, but not limited to, a liquid dielectric typematerial. For example, a liquid type dielectric type material may bedisposed by utilizing at least one of a spray type, roller type, and/ora squeegee type approach. It should be appreciated by those skilled inthe relevant art that the substrate material 112 may be disposed on thefirst surface 104 of the substrate 102 by a wide variety of approaches.Accordingly, the claimed subject matter is not limited to any oneparticular approach.

In the embodiment illustrated in FIG. 1, second conductive pattern 116is shown on the second surface 114 of substrate material 112. However,as previously described, second conductive pattern 116 may be disposedon the substrate material 112 utilizing a variety of approaches such as,but not limited to, a lamination approach, lithography approach, etchingapproach, a screen printing type approach, a laser structuring typeapproach, and so forth. That is, second conductive pattern 116 may bedisposed as part of the process of providing substrate material 112, andaccordingly, the claimed subject matter is not limited in theserespects.

In the embodiment of FIG. 1, second conductive pattern 116 substantiallymatches the pattern of the first conductive pattern 108 to facilitatewrapping of the permeability material 110 between the first conductivepattern 108 and the second conductive pattern 116. Additionally, firstconductive pattern 108 and second conductive pattern 116 may beelectrically coupled by various vias and/or interconnects as will bedescribed in detail herein. Moreover, plated through hole (PTH) vias canbe used to interconnect the layers with conductive patterns on the topand bottom surfaces. Techniques for implementing PTH vias are well knownto those of ordinary skill in the art. Together, first conductivepattern 108 and the second conductive pattern 116 cooperate to becapable of facilitating magnetic properties of the permeability material110. For example, first conductive pattern 108 and second conductivepattern 116 may cooperate to be capable of inducing a magnetic fieldupon the permeability material 110.

FIGS. 2A-2B illustrate a top view and a sectional view of a substratehaving a feature in accordance with one embodiment. In FIG. 2A, asubstrate 200 may have a surface 202 and a feature 204. As shown in FIG.2B, feature 204 may be formed into the substrate 204 below the surface202. In this embodiment, the feature 204 may have a substantiallytoroidal shape formed as a depression type feature into the substrate200. As previously described, feature 204 may be formed by utilizing awide variety of approaches and may have a variety of shapes, andaccordingly, the claimed subject matter is not limited in theserespects.

FIGS. 3A-3C illustrate a top view, a section view, and a detail view ofa substrate having a feature and a conductive pattern disposed withinthe feature in accordance with one embodiment. Referring to FIG. 3A, asubstrate 300 may have a surface 302, a feature 304, and a conductivepattern 306. As shown in FIG. 3A, feature 304 may have a substantiallytoroidal type shape, and correspondingly, conductive pattern 306 may bepatterned circumferentially around the feature 304 (i.e., a wheel typepattern radiating from the center of the toroid). Turning to FIG. 3B, inthe illustrated embodiment, conductive pattern 306 has a portion on thesurface 302 and partly covers the walls of the feature 304 (i.e.,feature areas below surface 302). Detail 308 is illustrated in FIG. 3C,where conductive pattern 306 is shown provided on surface 302, insidefeature 304, and back on surface 302.

As previously described, once the conductive pattern 306 is disposed onthe feature 304, a permeability material may be disposed within thefeature 304. A substrate material may be disposed on the surface 302having a second conductive pattern. Various conductive paths such as,but not limited to, vias and/or interconnects (not shown) may be formedand utilized to electrically couple the two conductive patterns, therebyforming a winding type structure around a permeability material.

FIG. 4 illustrates a perspective exploded view of a magnetic componentin accordance with another embodiment. In FIG. 4, similar to magneticcomponent 100 (shown in FIG. 1), magnetic component 400 may include asubstrate 400, a first surface 404, a feature 406, a first conductivepattern 408, a substrate material 410, a second surface 412, and asecond conductive pattern 414. However, in this embodiment, apermeability material (not shown) may be relatively large based at leastin part on its application. Accordingly, a second feature 416 may beformed on the substrate material 410 to facilitate accommodation of thepermeability material. As shown, second conductive pattern 414 may bedisposed to at least partially cover the surfaces of the second feature416. As previously described, substrate material 410 may be disposed onthe substrate utilizing various approaches such as, but not limited to,a lamination type approach, where a sheet of substrate material having asecond feature may be disposed on a substrate. Alternatively, substratematerial may be disposed utilizing an etching type approach, where thesecond feature 416 may be the result of covering the permeabilitymaterial that extends out of the surface 404. Further, substratematerial may be disposed utilizing a spray type, roller type, and/or asqueegee type approach. Accordingly, the claimed subject matter is notlimited to a particular approach.

Here again, various approaches may be utilized for disposing conductivepatterns. For example, one such approach may be a lithography typeapproach utilizing various etching methods, and another approach may beto utilize a stamping type approach, a laser structuring type approach,and so forth. Conductive patterns may be patterned to facilitate variousmagnetic properties for various magnetic components based at least inpart on their applications. Further, because an approach that may beutilized in providing the number of conductive patterns may be of alithography type approach, laser structuring type approach, etc.,precision of the conductive patterns may be relatively high based atleast in part on the type approaches utilized such as, but not limitedto, a high aspect lithography approach of ultraviolet photolithography,and accordingly, the claimed subject matter is not limited to aparticular approach.

In various embodiments, one or more magnetic components may be formed ona single substrate. Additionally, because the magnetic properties of amagnetic component may be based at least in part on its conductivepattern, its feature size, permeability material utilized, and/or soforth, more than a single type of magnetic component may be formed froma single substrate, and accordingly, the claimed subject matter is notlimited in these respects.

Examples of magnetic components may include a magnetic componentincluding a substrate having a feature, a first conductive pattern, apermeability material, a substrate material, and a second conductivepattern, where the first conductive pattern and the second conductivepattern cooperate to be capable of facilitating magnetic properties ofthe permeability material for various applications. Various applicationsmay include applications such as, but not limited to a dual common modefilter, a single common mode filter, a single inductor, an isolationtransformer, and so forth, and accordingly, the claimed subject matteris not limited in these respects. Various embodiments of variousmagnetic components, without limitations, may be illustrated in FIG. 5through FIG. 8.

Turning now to FIG. 5, a magnetic component 500 may include a substrate(not shown) having a feature 502, a first conductive pattern 504, apermeability material 506, a substrate material (not shown), and asecond conductive pattern 508. The first conductive pattern 504 and thesecond conductive pattern 508 cooperate to be capable of facilitatingmagnetic properties of the permeability material 506, and in thisparticular embodiment, magnetic component 500 may be capable of beingutilized as a dual common mode filter (i.e., a common mode filter typefunctionality) as shown by related circuit illustration 510. It shouldbe appreciated that the substrate and substrate material are not shownin order to better illustrate the embodiment.

FIG. 6 illustrates a schematic of a magnetic component in accordancewith another embodiment. In FIG. 6, magnetic component 600 may include asubstrate (not shown) having a feature 602, a first conductive pattern604, a permeability material 606, a substrate material (not shown), anda second conductive pattern 608. The first conductive pattern 604 andthe second conductive pattern 608 cooperate to be capable offacilitating magnetic properties of the permeability material 606, andin this particular embodiment, magnetic component 600 may be capable ofbeing utilized as a single common mode filter (i.e., a single commonmode filter functionality) as shown by related circuit illustration 610.

FIG. 7 illustrates a schematic of a magnetic component in accordancewith another embodiment. In FIG. 7, magnetic component 700 may include asubstrate (not shown) having a feature 702, a first conductive pattern704, a permeability material 706, a substrate material (not shown), anda second conductive pattern 708. The first conductive pattern 704 andthe second conductive pattern 708 cooperate to be capable offacilitating magnetic properties of the permeability material 706, andin this particular embodiment, magnetic component 700 may be capable ofbeing utilized as a single inductor (i.e., an inductor typefunctionality) as shown by related circuit illustration 710.

FIG. 8 illustrates a schematic of a magnetic component in accordancewith another embodiment. In FIG. 8, magnetic component 800 may include asubstrate (not shown) having a feature 802, a first conductive pattern804, a permeability material 806, a substrate material (not shown), anda second conductive pattern 808. The first conductive pattern 804 andthe second conductive pattern 808 cooperate to be capable offacilitating magnetic properties of the permeability material 806, andin this particular embodiment, magnetic component 800 may be capable ofbeing utilized as an isolation transformer (i.e., a transformer typefunctionality) as shown by related circuit illustration 810.

FIG. 9 illustrates a flow chart of one embodiment of a process forproducing a magnetic component. As illustrated by flow chart 900 in FIG.9, the process may start by providing a substrate, as indicated by block902. As previously described, substrate may be of wide variety ofmaterials that may be utilized to PCBs. Further, substrate may have afeature formed on the substrate utilizing a wide variety of approachesas previously described. In the embodiment of FIG. 9, a first conductivepattern may be disposed over the feature and the substrate, as indicatedby block 904. At block 906, a permeability material may be disposedwithin the feature. A substrate material may be disposed over thepermeability material and the substrate at block 908. At block 910, asecond conductive pattern may be disposed on the substrate material,thereby facilitating a winding of the conductive patterns around thepermeability material.

Gapping an Embedded Magnetic Device

Switch mode power conversion (SMPC) is widely used to implement highefficiency Alternating Current (AC)-to-Direct Current (DC) and DC-to-DCconverters. Inductors and transformers are used in SMPC applications forenergy storage and to filter switching noise. In most applications, thecurrent in the inductive windings will have both an AC and DC component.Inductors are often implemented by winding a conductive coil around aferromagnetic core. The amount of inductance is dependent on the numberof windings and permeability of the core. When an electric current isapplied to the windings, a magnetic field (H) will develop around theconductive windings and induce a magnetic flux (B) in the ferromagneticcore material. The H field is proportional to the driving current andthe B field is proportional to the applied voltage. At low current andvoltage levels, H and B have a linear relationship. Magnetic saturationoccurs when excessive amounts of current are applied and the H fieldincreases to the point where the relationship between H and B is nolonger linear. When the core material saturates, the magnitude of theflux density, B, levels off and increasing the magnetic H field will notinduce additional magnetic flux. If excessive current is driven into thecore, it will saturate and not be able to sustain larger voltages. Inthe case of an output filter in a power converter, excessive DC currentwill cause ferromagnetic material to saturate, degrade the inductance,and change the filter performance characteristics.

Transformers are primarily intended to be used as AC devices. Switchingthe winding current in both a positive and negative direction willeffectively switch the direction that the magnetic flux flows within thecore material. If switched at high frequencies, the induced fluxescancel out within each duty cycle. As noted earlier, however, the outputof a power converter can have both AC and DC current components. DCcurrent flowing through the output windings of the power transformer cansaturate the ferromagnetic core and minimize its ability to store energyand filter noise.

For toroid (ring) shaped cores, designers often cut a gap (slot) out ofthe core (denoted herein as gapping) to extend its ability to handle DCcurrents. The gap effectively adds reluctance (resistance to the flow ofmagnetic flux) to the ferromagnetic core and reduces the sensitivity ofthe core to the driving current and the associated H field. The corepermeability and inductance is reduced dramatically, yet the gappingallows the core to operate with much higher currents before saturationoccurs. In the case of the power inductor, gapping allows the inductorto pass DC current to the load, while still serving as a filter to ACcurrents and high frequency switching noise.

Inductors and transformers come in many shapes and sizes. FIGS. 10a and10b depict inductors wound on solenoid 1001 (FIG. 10a ) and toroid 1002(FIG. 10b ) shaped cores. In both FIGS. 10a and 10b , we see a depictionof the magnetic flux flowing in the two inductor shapes. Chip inductorsand drum cores are widely used in electronic systems and are essentiallywound on solenoid shaped cores. While chip inductors find widespreaduse, they are not the most efficient and can cause radiated andconducted noise problems due to the magnetic flux energy emanating fromeach end of the device. This radiated energy causes noise and candisturb nearby components. Given the same volume of ferromagneticmaterial, the toroid device 1002 (FIG. 10b ) is more efficient in thatit will produce much more inductance per winding. Also, the toroiddevice 1002 (FIG. 10b ) will exhibit lower power loss and noiseemissions; because the magnetic flux, B, has a circular path within thehigh permeability ferromagnetic material and will remain containedwithin the core structure. The toroid core structure is preferred forcontrolling noise and maximizing the system efficiency.

Winding solenoids can be automated. Historically, it has been easier tomanufacture inductors and transformers on solenoid bobbins rather thanon toroid shaped cores. While there are automated winding machinesdesigned to handle large toroid cores (<10 mm diameter), winding wire ona small toroid has defied automation. Plus, machining a gap into a smallcore requires precision fixtures to hold the core while it is being cutwith either a diamond saw or laser. Once the core is gapped, the cutadds complications when applying the wire windings, whether it is woundmanually or automatically.

An Example Embodiment for Gapping an Embedded Magnetic Device

Embedded magnetic construction gets around the challenges of gapping andwinding. Rather than wind wire around the ring structure, the toroidcores in an example embodiment are embedded into a substrate and thewindings are applied using standard Printed Circuit Board (PCB)processes. Multiple devices can be arrayed into a panel format andproduced in an automated and batch process. Once the inductor ortransformer is implemented in the PCB format, it can be easily handledon a machining station. In the case of mechanical gap cutting with aband saw, diamond wheel or cutting device, the panel can first besegmented into 1×N arrays of devices. In that smaller format, the 1xNarrays can be fastened to an x-y machining station and gaps can be cutinto the edge of each device. If laser or water jet milling is employed,the panel array can be left intact and the cutting can be applied fromeither the top, bottom or both surfaces. Laser cutting is preferred inthat it can provide narrow and precision gaps into the PCB andferromagnetic core. The cutting section of the embedded magnetic deviceis a composite of the substrate material, encapsulation material and theferromagnetic material. Each of these materials has different machiningproperties, so some test and experimentation is required to optimize thecut. With a laser, there are a number of variables that can be used tocontrol the width and speed of the cut. These variables include, yet arenot limited to; beam wavelength, beam power, beam width/aperture, beampulse width (rate), and feed rate. The objective is to simply cut thegap into the ferromagnetic core. Yet, the cutting path should extend asmall distance beyond the inner and outer radius of the ferromagneticcore, to compensate for any positioning tolerances.

FIGS. 11a and 11b show a top view and isometric view of an embeddedmagnetic device (e.g., inductor) 1100 in an example embodiment. The viaarrays 1102 that interconnect the top and bottom layers can bepositioned to provide clearance for the laser or cutting tool. Thewindings 1104 of the embedded magnetic device 1100 are imaged and etchedonto the PCB panel. The cutting path 1106 can be marked with either anetched trace or printed with ink on the panel surface. Marking the pathcan help during the machine set-up and inspection after the cut has beencompleted. FIGS. 11a and 11b illustrate views of an embedded magneticinductor 1100 in an example embodiment and the laser cutting path 1106to perform gapping of the embedded magnetic inductor 1100.

The various embodiments disclosed herein are primarily described withtoroid shaped core structures. However, the various embodimentsdisclosed herein also apply to other shapes of core structures. Othershapes can include an oval, rectangle, and multi-hole core structures.FIGS. 12a and 12b show top views of examples of embedded magneticdevices implemented on rectangular 1201 and multi-hole (binocular) 1202core structures.

There may be some applications where it is not necessary to cut theferromagnetic core all the way through. An example is when it is simplydesired to trim or tune the inductance value. In this instance, thelaser or cutting tool would only cut into a fraction of the width of theferromagnetic core. Here, it is beneficial to monitor the inductance orother electrical characteristics of the embedded magnetic device duringthe cutting process and use the inductance value or other monitoredelectrical characteristics to control the cutting tool. FIG. 13 shows anisometric diagram of an embedded magnetic device 1300 in an exampleembodiment being trimmed with a laser 1302 while the inductance of theembedded magnetic device 1300 is monitored by an inductance meter 1304.As such, FIG. 13 illustrates an example embodiment of an active trimmingand gapping system and method.

After the gap is applied, it may be beneficial to remove any debris fromthe gap. This can be achieved with forced air, forced water, forcedsolvent or by ultrasonic cleaning methods. Chemical and plasma etchingmay also be employed to remove debris from the gap. In most PCBapplications, a solder mask or conformal coating is applied to the topand bottom surfaces to provide voltage isolation and environmentalprotection. For the same reasons, it is beneficial to fill or coat theapplied gap. This can be achieved by filling or coating the gap withepoxy, polyimide or another gap filling material. The fill or coatingmaterial can be applied by spaying, painting, screen printing,sputtering, or other suitable method.

Many embedded magnetic inductive devices can be implemented with twoprinted circuit layers. There will be some instances where more layersare required. For a power transformer, it is useful to put the primarywindings on the inner layers and secondary windings on outer layers.When more than two layers are applied, it is best to cut the gap beforeapplying the outer layers. Prior to applying the outer layers, the gapcan be filled with epoxy, polymer or other gap filling materials, asdescribed above. An alternative is to simply leave the gap open andsimply let the gap fill with epoxy during the lamination of the outerlayers.

FIG. 14 depicts a four layer embedded magnetic device 1400 in an exampleembodiment where the gap 1402 is cut in the inner layers 1404 afterapplication of the inner layers 1404 and before the inner layers 1404are covered by the outer layers 1406. For applications like a powerconverter, it is beneficial to have the power inductor or transformerintegrated into the PCB format, upon which other active and passivedevices can be placed to produce a subsystem module. In theseapplications, the gapping process provided by the various exampleembodiments described herein can be used to gap the embedded magneticdevice while enabling integration of the gapped embedded magnetic devicewith other active and passive devices on a PCB substrate.

FIGS. 15a and 15b depict how a power converter module 1500 in an exampleembodiment can be implemented with embedded magnetics. The powerinductor is often the largest component in the circuit. Embedding thepower inductor into the PCB substrate can greatly reduce the size of themodule. Similar to the four layer transformer of the example embodimentdescribed above, the gapped embedded magnetic device 1502 can beimplemented in the underlying layers. The gap 1504 can either be cut andfilled prior to applying the outer layers 1506 or cut and filled withepoxy during the lamination process. FIGS. 15a and 15b illustrate anexample embodiment of a power converter 1500 constructed with anembedded magnetic device 1502, wherein the gapping process provided bythe various example embodiments described herein can be used to gap theembedded magnetic device 1502 while enabling integration of the gappedembedded magnetic device 1502 with a power converter on a PCB substrate.

In various example embodiments, the gap can be applied at differentstages of the fabrication process flow. For mechanical gapping, it istypically best to machine the gap after the device fabrication iscomplete. For laser, water jet, or plasma gapping, the gap can beapplied at various stages of the fabrication process. FIGS. 16a, 16b,and 16c depict variations of different stages of the fabrication processflow of example embodiments where the trim-cut or gap can be appliedduring various stages of the device fabrication process.

FIG. 17 is a flow chart illustrating an example embodiment of a method1700 as described herein. The method 1700 of the example embodimentcomprises: forming a feature on a substrate, the feature being adepression defining an inside surface (operation 1710); disposing afirst conductive pattern on the substrate and the inside surface of thefeature (operation 1720); disposing a permeability material on theinside surface of the feature and the first conductive pattern(operation 1730); disposing a substrate material on the substrate andthe feature (operation 1740); disposing a second conductive pattern onthe substrate material, the second conductive pattern substantiallymatching the first conductive pattern to wrap the permeability materialbetween the first conductive pattern and the second conductive patternproducing a winding type structure electrically coupling the firstconductive pattern and the second conductive pattern in electricalconnection to define at least one electrical circuit to facilitate amagnetic field in the permeability material (operation 1750); andgapping the permeability material to remove at least a portion of thepermeability material to produce a gap in the at least a portion of thepermeability material (operation 1760).

While there has been illustrated and/or described what are presentlyconsidered to be example embodiments of claimed subject matter, it willbe understood by those of ordinary skill in the art that various othermodifications may be made, and/or equivalents may be substituted,without departing from the true scope of claimed subject matter.Additionally, many modifications may be made to adapt a particularsituation to the teachings of claimed subject matter without departingfrom subject matter that is claimed. Therefore, it is intended that thepatent not be limited to the particular embodiments disclosed, but thatit covers all embodiments falling within the scope of the appendedclaims.

What is claimed is:
 1. An embedded magnetic device comprising: a featureformed on a substrate, the feature being a depression defining an insidesurface, the feature having a first conductive pattern disposed on thesubstrate and the inside surface of the feature; permeability materialdisposed on the inside surface of the feature and the first conductivepattern; substrate material disposed on the substrate and the feature; asecond conductive pattern disposed on the substrate material, the secondconductive pattern substantially matching the first conductive patternto wrap the permeability material between the first conductive patternand the second conductive pattern producing a winding type structureelectrically coupling the first conductive pattern and the secondconductive pattern in electrical connection to define at least oneelectrical circuit to facilitate a magnetic field in the permeabilitymaterial; and a gap in at least a portion of the permeability material.2. The embedded magnetic device of claim 1, wherein the at least oneelectrical circuit defines at least two interleaved electrical paths toproduce a single inductor type functionality.
 3. The embedded magneticdevice of claim 1, wherein the at least one electrical circuit definesat least two interleaved electrical paths to produce a transformer typefunctionality.
 4. The embedded magnetic device of claim 1, furtherincluding a power converter embedded into the substrate.
 5. The embeddedmagnetic device of claim 1 wherein the permeability material is aferromagnetic core disposed into the substrate and encapsulated and thegap is applied after encapsulation and prior to disposing subsequentsubstrate layers and conductive patterns.
 6. The embedded magneticdevice of claim 1 wherein the gap is applied after the first and secondsubstrate layers and conductive patterns are applied.
 7. The embeddedmagnetic device of claim 1 wherein the inductance of the embeddedmagnetic device is trimmed or tuned while the inductance is monitored inreal-time.
 8. The embedded magnetic device of claim 1 wherein the gap iscut from both a top surface and a bottom surface of the substrate. 9.The embedded magnetic device of claim 1 being configured as a gappedembedded inductor integrated with a power converter on a printed circuitboard (PCB).
 10. The embedded magnetic device of claim 1 beingconfigured as a gapped embedded inductor of a power converter modulehaving substrate material disposed upon first and second conductivelayers and a third and fourth conductive pattern disposed on thesubstrate material where conductive circuitry is disposed to receiveadditional passive and active devices.
 11. The embedded magnetic deviceof claim 1 being configured as a gapped embedded transformer of a powerconverter module having substrate material disposed upon first andsecond conductive layers and a third and fourth conductive patterndisposed on the substrate material where conductive circuitry isdisposed to receive additional passive and active devices, the third andfourth conductive pattern serving as a printed circuit board (PCB) uponwhich other passive and active devices are disposed.
 12. The embeddedmagnetic device of claim 1 where the gap is a laser cut having a widthbased on laser power, laser beam width, position of laser focus, feedrate, pulse rate, and pulse duty cycle.
 13. The embedded magnetic deviceof claim 1 where the permeability material is a ferromagnetic corehaving a multi-hole core structure and either an oval or square shape.14. An embedded magnetic device comprising: a feature formed on asubstrate, the feature being a depression defining an inside surface,the feature having a first conductive pattern disposed on the substrateand the inside surface of the feature; permeability material disposed onthe inside surface of the feature and the first conductive pattern;substrate material disposed on the substrate and the feature; a secondconductive pattern disposed on the substrate material, the secondconductive pattern substantially matching the first conductive patternto wrap the permeability material between the first conductive patternand the second conductive pattern producing a winding type structureelectrically coupling the first conductive pattern and the secondconductive pattern in electrical connection to define at least oneelectrical circuit to facilitate a magnetic field in the permeabilitymaterial; a gap in at least a portion of the permeability material; thesubstrate material disposed upon the second conductive pattern; and athird and fourth conductive pattern disposed on the substrate material,the third and fourth conductive pattern wrapping the permeabilitymaterial producing a winding type structure electrically coupling thethird and fourth conductive patterns in electrical connection to defineat least one electrical circuit to facilitate a magnetic field in thepermeability material.
 15. The embedded magnetic device of claim 14being configured as a gapped embedded inductor and a printed circuitboard (PCB).
 16. The embedded magnetic device of claim 14 beingconfigured as gapped embedded transformer and a printed circuit board(PCB).
 17. The embedded magnetic device of claim 14, wherein the gap iscleaned with forced air, forced water, or ultrasonic cleaning toeliminate debris.
 18. The embedded magnetic device of claim 14, whereinthe gap is filled with epoxy, solder mask, polyimide, pre-preg, or gapfilling material.
 19. The embedded magnetic device of claim 14, whereinthe gap is filled with epoxy, solder mask, polyimide, pre-preg, or gapfilling material when the substrate material is disposed on thesubstrate.
 20. The embedded magnetic device of claim 14 where thepermeability material is a ferromagnetic core having a multi-hole corestructure and either an oval or square shape.
 21. The embedded magneticdevice of claim 14 including a marking on a top or bottom surface toprovide a target and facilitate laser set-up, step, and repeat cutting.